The_Complete_Chronicles_of_Narnia_(volumes_1-7,_in_order_of_publication)

"You may think it interesting," said Digory. "But you wouldn't like it if you had to sleep
there. How would you like to lie awake listening for Uncle Andrew's step to come
creeping along the passage to your room? And he has such awful eyes."
That was how Polly and Digory got to know one another: and as it was just the beginning
of the summer holidays and neither of them was going to the sea that year, they met
nearly every day.
Their adventures began chiefly because it was one of the wettest and coldest summers
there had been for years. That drove them to do indoor things: you might say, indoor
exploration. It is wonderful how much exploring you can do with a stump of candle in a
big house, or in a row of houses. Polly had discovered long ago that if you opened a
certain little door in the box-room attic of her house you would find the cistern and a dark
place behind it which you could get into by a little careful climbing. The dark place was
like a long tunnel with brick wall on one side and sloping roof on the other. In the roof
there were little chunks of light between the slates. There was no floor in this tunnel: you
had to step from rafter to rafter, and between them there was only plaster. If you stepped
on this you would find yourself falling through the ceiling of the room below. Polly had
used the bit of the tunnel just beside the cistern as a smugglers' cave. She had brought up
bits of old packing cases and the seats of broken kitchen chairs, and things of that sort,
and spread them across from rafter to rafter so as to make a bit of floor. Here she kept a
cash-box containing various treasures, and a story she was writing and usually a few
apples. She had often drunk a quiet bottle of ginger-beer in there: the old bottles made it
look more like a smugglers' cave.
Digory quite liked the cave (she wouldn't let him see the story) but he was more
interested in exploring.
"Look here," he said. "How long does this tunnel go on for? I mean, does it stop where
your house ends?"
"No," said Polly. "The walls don't go out to the roof. It goes on. I don't know how far."
"Then we could get the length of the whole row of houses."
"So we could," said Polly, "And oh, I say!"
"What?"
"We could get into the other houses."
"Yes, and get taken up for burglars! No thanks."
"Don't be so jolly clever. I was thinking of the house beyond yours." ,
"What about it?"